MainActivity.java

package com.kevalpatel2106;

import android.os.AsyncTask;
import android.os.Bundle;
import android.support.annotation.Nullable;
import android.support.v7.app.AppCompatActivity;
import android.widget.TextView;

/**
 * Created by Keval on 06/05/18.
 *
 * @author <a href="https://github.com/kevalpatel2106">kevalpatel2106</a>
 */
public class MainActivity extends AppCompatActivity {

    @Override
    protected void onCreate(@Nullable final Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        setContentView(R.layout.activity_main);

        new Thread(new Runnable() {
            @Override
            public void run() {
                //Here I am executing the task from diffrent Java thread.
                //So, It doesn't have looper.
                new CustomAsync().execute();
            }
        }).start();

    }

    //Custom async task that does nothing.
    class CustomAsync extends AsyncTask<Void, Void, Void> {


        @Override
        protected Void doInBackground(final Void... voids) {
            try {
                Thread.sleep(5000L);
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
            return null;
        }


        @Override
        protected void onPostExecute(final Void aVoid) {
            super.onPostExecute(aVoid);
            //Lets update the status text to "Done".
            //Task is finished.
            ((TextView)findViewById(R.id.status_tv)).setText("Done");
        }
    }
}